4N26FR2M Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N26FR2M is an optoisolator transistor with base output manufactured by onsemi, designed for high-voltage isolation applications. This component features a 7500Vpk isolation rating and operates across a temperature range of -55°C to 100°C. The part is currently classified as obsolete, making identification of suitable substitute components essential for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	4N26FR2M
Manufacturer	onsemi
Category	Optoisolators
Number of Channels	1
Voltage - Isolation	7500Vpk
Current Transfer Ratio (Min)	20% @ 10mA
Output Type	Transistor with Base
Voltage - Output (Max)	30V
Vce Saturation (Max)	500mV
Operating Temperature	-55°C ~ 100°C
Mounting Type	Surface Mount
Package / Case	6-SMD, Gull Wing
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the 4N26FR2M is determined by the following critical parameters:

Number of Channels: Must be 1 channel
Output Type: Must be Transistor with Base
Current Transfer Ratio (Min): Must be 20% @ 10mA or greater
Vce Saturation (Max): Must be 500mV or lower
Input Type: Must be DC
Voltage - Forward (Vf) (Typ): Must be 1.18V or 1.3V
Current - DC Forward (If) (Max): Must be 60mA or greater
Mounting Type and Package: Surface Mount 6-SMD preferred; Through Hole 6-DIP acceptable with design modification
Operating Temperature Range: Must support -55°C to 100°C or equivalent

The 4N26FR2M has two identified substitutes: the 4N26SR2M (onsemi, active status) and the 4N26 (Texas Instruments, active status). Both maintain core functional parameters while differing in isolation voltage rating and packaging configuration.

Parameter Comparison

Parameter	4N26FR2M (Main)	4N26SR2M (Substitute)	4N26 (Substitute)
Manufacturer	onsemi	onsemi	Texas Instruments
Product Status	Obsolete	Active	Active
Number of Channels	1	1	1
Voltage - Isolation	7500Vpk	4170Vrms	5000Vrms
Current Transfer Ratio (Min)	20% @ 10mA	20% @ 10mA	20% @ 10mA
Turn On / Turn Off Time (Typ)	2µs, 2µs	2µs, 2µs	—
Input Type	DC	DC	DC
Output Type	Transistor with Base	Transistor with Base	Transistor with Base
Voltage - Output (Max)	30V	30V	70V
Voltage - Forward (Vf) (Typ)	1.18V	1.18V	1.3V
Current - DC Forward (If) (Max)	60mA	60mA	60mA
Vce Saturation (Max)	500mV	500mV	500mV
Operating Temperature	-55°C ~ 100°C	-40°C ~ 100°C	-55°C ~ 100°C
Mounting Type	Surface Mount	Surface Mount	Through Hole
Package / Case	6-SMD, Gull Wing	6-SMD, Gull Wing	6-DIP (0.300", 7.62mm)
RoHS Status	—	ROHS3 Compliant	RoHS non-compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Affected

Engineering Selection Recommendations

4N26SR2M (onsemi) is the primary substitute for the 4N26FR2M. Both components are manufactured by onsemi, share identical surface-mount 6-SMD packaging, and maintain matching electrical characteristics including current transfer ratio, switching times, and saturation voltage. The 4N26SR2M is currently in active production status with ROHS3 compliance and REACH unaffected designation. The isolation voltage is reduced from 7500Vpk to 4170Vrms; this substitution is valid only when the application isolation requirement does not exceed 4170Vrms.

4N26 (Texas Instruments) serves as an alternative substitute when higher output voltage capability (70V maximum versus 30V) is required. This component maintains the same current transfer ratio and saturation voltage specifications. However, substitution requires PCB redesign due to the transition from surface-mount 6-SMD to through-hole 6-DIP packaging. The Texas Instruments 4N26 operates across the full -55°C to 100°C temperature range matching the original part. Note that this variant is RoHS non-compliant and REACH affected, which may impact regulatory compliance requirements for the end application.

Frequently Asked Questions (FAQ)

Q: Can the 4N26SR2M directly replace the 4N26FR2M without PCB modification?

A: Yes, the 4N26SR2M is a direct pin-compatible replacement in the same 6-SMD, Gull Wing package. No PCB redesign is required. Verify that your application isolation voltage requirement does not exceed 4170Vrms.

Q: What is the key difference between the 4N26FR2M and 4N26SR2M?

A: The primary difference is isolation voltage rating: 4N26FR2M provides 7500Vpk isolation, while 4N26SR2M provides 4170Vrms isolation. All other electrical parameters, including current transfer ratio, switching times, and output voltage limits, are identical. The 4N26SR2M is in active production status.

Q: Can I use the Texas Instruments 4N26 as a drop-in replacement?

A: The Texas Instruments 4N26 is not a drop-in replacement due to packaging differences. The original 4N26FR2M uses surface-mount 6-SMD packaging, while the Texas Instruments variant uses through-hole 6-DIP packaging. PCB redesign and component placement modification are required. Additionally, verify compliance requirements, as this part is RoHS non-compliant and REACH affected.

Q: What is the minimum operating temperature for the 4N26SR2M?

A: The 4N26SR2M operates from -40°C to 100°C, which is 15°C higher than the original 4N26FR2M (-55°C to 100°C). If your application requires operation below -40°C, the 4N26SR2M is not suitable; use the Texas Instruments 4N26 instead.

Q: Are there any compliance differences between these substitutes?

A: Yes. The 4N26SR2M is ROHS3 compliant and REACH unaffected. The Texas Instruments 4N26 is RoHS non-compliant and REACH affected. Select based on your product's regulatory requirements.

Q: What parameters must match for a valid substitution?

A: Critical matching parameters are: single channel configuration, transistor with base output type, minimum 20% current transfer ratio at 10mA, maximum 500mV Vce saturation, and DC input type. Isolation voltage, operating temperature range, and packaging must be evaluated against specific application requirements.

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